get_user_leagues

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds value by specifying the return contents (league_id, draft_id, settings, scoring, roster positions, status, previous-league linkage) and the prerequisite on user_id. It does not contradict annotations and offers context beyond them.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences: the first states the core purpose, and the second lists expectations and usage context. It is front-loaded, free of fluff, and each sentence earns its place. No unnecessary repetition or filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a list-and-return tool with no output schema, the description adequately explains what it returns, the prerequisite (get_user), and when to use it. It covers everything an agent needs to invoke it correctly. The lack of pagination or error details is minor given the tool's simplicity and the annotations covering the safety profile.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so each parameter is already documented (e.g., user_id says 'Numeric Sleeper user_id obtained from get_user, not a username'). The tool description does not add parameter-specific meaning beyond what the schema provides; it only reiterates usage in the body. With full schema coverage, the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb (List), resource (Sleeper leagues), and scope (belonging to a user for a sport and season). It also lists the returned metadata fields, making the tool's function unambiguous. It clearly distinguishes from siblings like get_league (which retrieves a single league) and get_user (which resolves a user).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides explicit usage guidance: 'Resolve a username with get_user first' establishes a prerequisite, and 'Use this to discover league IDs before standings, matchup, roster, transaction, or playoff analysis' states the intended workflow. This clearly positions the tool relative to its siblings and prevents misuse.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.